From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <michael@ellerman.id.au>
Subject: Re: [PATCH] irqbalance, powerpc: add IRQs without settable SMP
	affinity to banned list
From: Michael Ellerman <michael@ellerman.id.au>
To: Michael Neuling <mikey@neuling.org>
In-Reply-To: <12972.1285135457@neuling.org>
References: <12972.1285135457@neuling.org>
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Date: Thu, 23 Sep 2010 18:22:39 +1000
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Cc: linuxppc-dev@ozlabs.org, Arjen Van De Ven <arjanvandeven@gmail.com>,
	linux-kernel@vger.kernel.org, Neil Horman <nhorman@gmail.com>
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On Wed, 2010-09-22 at 16:04 +1000, Michael Neuling wrote:
> When irqblance attempts writes to the IPI smp_affinity (ie.
> /proc/irq/16/smp_affinity in the above example) it fails but irqbalance
> ignores currently ignores this.
>=20
> This patch catches these write fails and in this case adds that IRQ
> number to the banned IRQ list.  This will catch the above IPI case and
> any other IRQ where the SMP affinity can't be set.

Cool!

> Index: irqbalance/irqlist.c
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> --- irqbalance.orig/irqlist.c
> +++ irqbalance/irqlist.c
> @@ -67,7 +67,7 @@
>  	DIR *dir;
>  	struct dirent *entry;
>  	char *c, *c2;
> -	int nr , count =3D 0;
> +	int nr , count =3D 0, can_set =3D 1;
>  	char buf[PATH_MAX];
>  	sprintf(buf, "/proc/irq/%i", number);
>  	dir =3D opendir(buf);
> @@ -80,7 +80,7 @@
>  			size_t size =3D 0;
>  			FILE *file;
>  			sprintf(buf, "/proc/irq/%i/smp_affinity", number);
> -			file =3D fopen(buf, "r");
> +			file =3D fopen(buf, "r+");
>  			if (!file)
>  				continue;
>  			if (getline(&line, &size, file)=3D=3D0) {
> @@ -89,7 +89,14 @@
>  				continue;
>  			}
>  			cpumask_parse_user(line, strlen(line), irq->mask);
> -			fclose(file);
> +			/*
> +			 * Check that we can write the affinity, if
> +			 * not take it out of the list.
> +			 */
> +			if (fwrite(line, strlen(line) - 1, 1, file) =3D=3D 0)

if (fputs(line, file) =3D=3D EOF)

?

cheers


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